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Do You Know What's in Your Sports Drink?

Carbohydrates go by a myriad of names. Get to know them, then put them to work.

by Pip Taylor

Sugar is a common suspect for many of our modern health woes, from rising rates of obesity to diabetes to poor dental health to cancer and even premature aging. As athletes we may think we’re immune to such concerns, but many of us still consume far too much sugar each day. Found in almost all packaged foods from breads and cereals to yogurt and ice cream, sugar is insidious—and especially so in popular sports foods.

While cutting back on sugar in our daily diet is worthwhile, consuming it in key workouts and races is beneficial. Its fast-acting, rapidly absorbed carbs replenish the ones our muscles burn in moderate to intense exercise. In short, sugar in motion is different to sugar consumed while at rest, so keep your sports snacks to sports alone.

The good news is that the sugars you’re likely to find in your sports drink, gel, bar or chew are usually minimal. So what are the differences, and what’s best?

Fun with fructose

The facts: One of the simplest sugars, fructose is found naturally in fruits. It's also a component of sucrose (together with glucose). It is found in almost all sports nutrition products—IRONMAN Perform, InfitIT, Gatorade Endurance and Hammer Gels for example.

The sweet: Fructose doesn't contribute to feelings of fullness, which is potentially beneficial when extra energy is necessary to support intense exercise.

The sour: Fructose is absorbed by the body differently than other sugars, and metabolized in the liver, meaning that more calories can be consumed and absorbed at once. Fructose does not stimulate an insulin response or the production of leptin—which helps regulate appetite and energy expenditure and intake—the way glucose does. This means that feelings of fullness are not triggered, encouraging you to eat more.

This is clearly not a good thing when calories are not required. For some, fructose is poorly tolerated and can lead to gastrointestinal distress like bloating and diarrhea. Test this out yourself by practicing with products that include fructose, and if you suffer, try fructose-free sports drinks, gels and bars and avoid fruit juice. Most people will tolerate fructose in small to moderate amounts but you need to find where your own tolerance lies.

Glorious glucose

The facts: Glucose is the sugar found in blood and stored in the muscles and liver in the form of glycogen. On labels, glucose may also refer somewhat misleadingly to dextrose, which has a slightly different chemical structure. Similarly, the term maltose refers to two glucose molecules joined together. Maltose is processed in the same way as glucose proper, providing a quick source of energy. It is found in sports products from drinks to gels to bars.

The sweet: Glycogen provides energy for working, active muscles, as well as the brain. Because glycogen stores are limited, carbs replenished during exercise help maintain high-intensity efforts.

The sour: During intense exercise, your body uses stored glycogen. Ingested glucose is used directly by working muscles, but you may not be able to digest and metabolize enough to keep pace. Using a second sugar in combination with glucose means more total carbohydrate can be used as distinct pathways are used for each sugar.

Sucrose savvy

Facts: The fancy name for what we commonly refer to as table sugar, sucrose is made up of one part glucose and one part fructose chemically bound together. Enzymes in the intestines break these two sugar molecules apart so they can be absorbed as single sugars. It is found in most sports drinks, gels and bars as one of, if not the primary source, of carbohydrate (along with fructose).

The sweet: Along with glucose and sodium, sucrose is important beyond providing energy: It facilitates fluid uptake across intestinal cell membranes—vital for effective hydration.

The sour: Like any of the sugars, too much of a good thing can be detrimental. Consuming drinks, or combinations of gels, bars and drinks with too high a concentration will slow gastric emptying, increase the likelihood of gastric distress and slow fluid absorption.

Maltodextrin mix-in

Facts: A sweet, easily digestible carbohydrate commonly made from rice, corn or potato starch found in varying quantities in most sports bars, gels and many sports drink mixes. Gels in particular usually contain maltodextrin because it is less sweet—ideal for keeping concentrated gels palatable, yet still delivering the desired amount of carbohydrates.

The sweet: Maltodextrin is easily digested in the stomach and rapidly metabolized for instant energy during exercise. It allows manufacturers to increase the carbohydrate content of products without making them sickly sweet.

The sour: A high concentration of this sugar can cause pressure in the intestinal tract, and force water back in and away from blood and working muscles. This can lead to dehydration, one of the major causes of gastrointestinal distress such as nausea, bloating, diarrhea and a "sloshy" stomach.

Galactose greatness

Facts: When bound with glucose, this simple sugar found mainly in milk and whey-based forms the sugar lactose. It is found in many recovery drinks and powders.

The sweet: Even if you are lactose intolerant you can still safely absorb and use galactose.

The sour: While galactose is a simple sugar it is also slowly metabolized, meaning that it takes longer to reach working muscles than some other sugars. For an athlete in need of instant energy, this may not be ideal.